The theory of chimnies and fire-places investigated [electronic resource] : the principle of those recommended by Count Rumford, fully explained, and their Construction Improved: and a Great Improvement, on a Principle Very Little Known, and in a Manner Never Practised. To which is added, a method of preparing houses and Ships, at Little Expence, in such a manner, that, in of fire, it may be extinguished with the Utmost Ease and Certainty. By Thomas Danforth, Esq. Formerly a Fellow of the Corporation of Harvard University, at Cambridge, in America.